Optical fibers are commonly used in medical applications. Optical fibers may be used in numerous procedures to act as optical waveguides for carrying light energy from a laser to a target body region to deliver energy to the target region. For example, in lithotripsy procedures, optical fibers are delivered through an endoscope—e.g., a cystoscope, ureteroscope, renoscope, or nephroscope—and are used to transmit light pulses from a laser source to a location within the body to break up and remove urinary stones.
Glass-clad optical fibers are commonly used in medical applications for delivery of laser energy. The fibers are often terminated with connectors that allow the optical fibers to couple and uncouple from laser delivery systems without compromising the alignment of the optical fiber system. Traditionally, fiber connector terminations often included adhesives to secure the optical fiber to the surrounding glass ferrule; however, issues of outgassing caused contamination of the laser output lens or, in some cases, caused the fiber termination to catastrophically fail.
To overcome the outgassing issues, methods of forming connector terminations were developed that reduced the use of adhesives or avoided the use of adhesives altogether. One solution was to directly fuse the optical fiber core and glass cladding to a surrounding glass ferrule at the termination to create a monolithic glass end that both secures the fiber to the ferrule and aligns the fiber within the ferrule without the use of adhesives. To fuse the fiber and the ferrule to one another at the connector termination, heat may be applied around the sides of the proximal end of the fiber and ferrule and to the proximal face of the connector termination, as is described in greater detail in U.S. Pat. No. 6,282,349, incorporated herein by reference in its entirety.
Yet, fused connector terminations require precise positioning between the fiber, ferrule, and heat source(s) in order to achieve the desired geometries for high coupling efficiency from the laser energy into a fiber body. Creating smooth and consistent concave- or convex-shaped connector terminations on the proximal face and controlling the fusion of the ferrule and the optical fiber along the sides, both of which are important for the coupling efficiency of the manufactured connector termination, can become an issue with fused connectors. Coupling efficiency is affected by, among other things, (i) the concentricity of the optical fiber within the fused ferrule, (ii) the geometry and depth of the concave (or convex) fused terminal surface, (iii) the smoothness of the fused terminal surface, and (iv) the shape and taper ratio of the tapered fiber, for example.
Currently, there is no way of controlling the fusion process in real time to ensure that the finished, fused connector termination has satisfactory coupling efficiency. Instead, heat is applied to the glass fiber and ferrule to fuse them together, and then post-fusion inspections are carried out to determine whether the fused connector meets manufacturing requirements. This uncontrolled manufacturing method may lead to large amounts of waste or manufacturing inefficiencies, because improperly fused connectors must be discarded.
As a result, a need exists for methods of manufacturing fused connector terminations that allows for tighter control of the fusion process. Specifically, a need exists for a method that allow for real-time assessment and control of the fusion process to promote increased coupling efficiency of the manufactured connectors and reduce waste.
The devices and methods of the current disclosure may rectify some of the deficiencies described above or address other aspects of the prior art.